Hold back valve device



Oct. 4, 1932. 1 Q MCCUNE HOLD-BACK VALVE DEVICE Filed Sept. 20. 1930 INVENTOR.

JOSEPH C- MCCUNE ATTORNEY.

Patented 4, 1932 ffgU-NITED STATES PATENT Orsicl:

JosEPiIIc. NICCUNE, OELEDGEWOOE, PENNSYLVANIA, AssIGNoR To THE WESTINGIIOUSE AIE BRAKE COMPANY, OE WILivIERnING, PENNSYLVANIA, A VcoI:.PoiaA'J.IoN 0E HOLD yPACK VALVE DEVICE Appiicatfion meid `septemimzo, 1930. serial No. 453,203.

- f This invention relatesV to viluid pressure brakesQandmore particularly to a. iiuid pres-y sure brake equipmentin which anemergency application lo f'thebrakes isV eected upon a '5 fsudde'n'reduction in brake pipe pressure;

V 'Wh'en an emergency application oit the Vbrakes is'` eected, either bymoving the en- Y tg'ineers brake valveto emergencyposition or 'by a rupture of the ybrake pipe, the brakes lo `on the carsadjacentfto the point at which the sudden reductionin brake pipe pressure is initiated, are applied With great `force in 'advance of the lapplication of the brakes on y the other carsV of `the train This isliable z to causea pull in tvvo ofthe train or an internal collision, due to the running in or out of i .theslalck in the train. Y Y Y VOne object of my invention isl to' provide means for holdingrback or delaying the application of the brakes oncars adjacent to fthepoint where a sudden reduction in brake 'pipepressure is initiated.

Other Ob'ects and advantages Will appear Vin the following more detailed description of the invention.' v

In the accompanying drawing; Fig. 1 isa 'i diagrammatic vievv,part-ly in'section, of a car `fluid pressure brake equipment embodying my invention; and Fig. 2 a section on'the line -'2-2ofFg'-1`. A Y y i i' The iiuid pressure brake equipment yshown vinFigj'l comprises a triple-valve device 1,

an auxiliary reservoir 2, a brake cylinder 3,'

abrake pipe 4, and ahold back valve device 5.

"- The triple valve device 1 may comprise the usual parts including a piston 7 contained in piston chamber 8, which chamber Ais connected to the brake pipe 4, and a main slide 'valve 9 -andlafgraduating slide valve 10 adapted to '40 be operated by piston 7, and contained in a f valve chamber 11vvhich is connected to the auxiliary reservoiri 2.

The triple valve casing also Vcontains a ,i quickvaction valve device comprising a pis-y ton 12, avent valve 13 adapted to be operated by said piston, and a check valve 14.

The hold back valvedevice 5 comprises a casing,

the triple valve device 1 and the auxiliaryy reservoir 2, and having a piston chamber 15 Which may be interposed between A ton 16 Yis such thatga sucient differential of ,pressures to move the piston from its' seat.

Vcontaining a piston 16 subject to the pressure of a coil spring 17. The pist-on chamber 15 lis yconnected by pipe 18 to the brake pipe 4 and the piston 16 has a lseat ring 19 at one side adapted to engage aseat rib 2.0,-the exposed area ofthe' piston Within the seat rib `2O. being'exposed to auxiliary reservoir pressure. l

A valve- 21 contained in valve chamber 22, which is open to the auxiliary reservoir 2 through' passage 23, is provided With a vfinged section 24, and a stemk 25, carried by piston 16 is adapted to engage said member. rlhe valve 21 is actedy upon by` a spring v26, which urges said valve to its seat. The .stem 25 extends through an openingin a partition Wall of the hold back valve casing andsaid opening is such as to provide a restricted flow communication from the auxiliary reservoir 2 to passage 27, leading to Vvalve chamber 11. jj

i In operation, when the brake pipe 4iis 4charged with lluidunder pressure, fluid iioWs from the triple valve piston chamber '8 :through the usual feed groove 33 around the triple valve piston 7, charging the valve chamber 11 and the auxiliaryreservoir 2 With fluid under pressure.

Fluid under pressure in the brake pipe flows through pipe 18 to piston chamber 15 of the hold back valve device and the auxiliary reservoir pressure acting on the inner seated area of thev piston 16 being equal to the brake f pipe pressure, vthe piston 16 is held seated on the seat rib 2O by spring 17.` The valve 21 is thus normally held unseated, so that a large opening is provided to permit flow of iiuid from the auxiliary reservoir 2 to the valve chamber 11, by Way of passage 23, past the open valve 21, to passage 27. y When La sudden reduction in brake pipe pressure is initiated,`either bylmoving the engineers brake valve to emergency position or bya rupture of the brake pipe, the triple valve piston 7 ismoved out to emergency application position to effect an emergency application of the brakes inthe usual manner.

The force of the spring 17 acting on pisi will notbe obtained except when the rateoi' pressure is initiated. On such cars, the pis-v ton 16,'Will .be moved from its seat, permitting "sudden reductionin `brake pipe pressure is the valve. v21 to seat sofas to cutoff communication from the auxiliaryreservoir to thevalve chamber 11, by Way of the large opening 1n-V cluding the passage23. kWith the valve 21 seated, liuid under pressureflcanonly flovvfV from the auxiliary reservoir 2 tovalve vcharnberj 11 by Way ofthe `restricted communica# tiony provided around thenstem 25. As a result of the restricted flow of yfluid from the Vauxiliary reservoir, the triple val've devices, f

on cars adjacentl tothepoint at/Which the initiated, are prevented from eecting a sudp Vden buildup of brake cylinder pressure. rIhis hold back ofthe building up of presl 25 sure inthe brake cylinders on cars adjacent to thelpoint at Which the sudden reduction in i brake pipe pressure is initiated, provides time for the brakes vto be applied on the othercars ""'offth'e train',so that the train isnot pulled rv intvvonor do internalloollisions occur, duev tothe running in and 'out of the-slack in Y opposing 'pressures oftheibrakepipe and the auxiliary reservoir for controlling the V opera- Vthe train.

M After a time,the fluid pressures on opposite `sidesiof the piston 16 equalize suciently to permit the spring 17 to return the piston 16 1 to' its seat, so that the valve 21 is again 'unf hseated, permitting the usual flow of Huid-from vthe auxiliary reservoir to the valvechamber While one illustrative embodiment-of l`the `*invention has been described in detail, it is not myfintention to limit its scopeto that embodiment or otherwisethan by the terms Having nowdescribed my invention, What I claim as nevv and desire to secure by Letters Patent,A is

1.*In a fluid pressure brake, the combina tion vWith a brake pipe, auxiliary reservoir, brake cylinder, andan equalizing valve deviceV operated upon a reduction in brake pipe pressure for supplyingfluid .under pressure from the auxiliary reservoir,k Vto the brake cylinderfof means operatedupon an emergeney rate of reduction in brake pipe pres-4 I .sure exceeding a predetermined rate for restrietingtliefloW-ofuid from Vthe auxiliaryv l Vreservoir Vto, said brake p cylinder. l. 2In a fluid-pressure brake, the cornbinaj 4tion-.WithV Vfa brake pipe', lauxiliary reservoir,

cylinder, of ymea-:ris operated' only when the :Y

Ytion of said valve. i Y Y h 5. vIn Sa iiuid pressure brake,fthe con1bina tion Yvvith a `brake pipe,:auxiliary reservoir, brake cylinder, andanequalizing valve-de'- xvic'e operated vupon a reduction in brake pipe pressure. forV supplying iiuid underpressure from the auxiliary reservoir. tothe brake;

rate of reduction y,injbrake ypipe pressure is higher than a predeterminedV emergency rate for restricting communication through which fluid is supplied from the auxiliary yreservoir to saidfbrake cylinder.

`3. In a fluidrpressureY brake, the colnbina-V tion With. a brake pipe, auxiliary reservoir, brake cylinder, and an equalizlngvalve device movable to'emergencyposition. upon a' sudden reduction in 'bralze pipe pressure, in which fluid under p'ressureis supplied from the auxiliary reservoir to thebrake cylinder, or valve means operated only When the sudden reduction in brake pipe pressure is at a predetermined high ratefor'V restricting 'communication; through which said lequalizing 4.V y In a fluid pressureibralrefthe 'combination vvith-y a brakeA pipe,-auxiliary reservoir,

auxiliary reseryoir to'.` said `eouial'izing. valve Vdev-ice andcemprsinga "valve operable to close communlcatl'on'through 'said large openl ing, and aj movable abutment subj'ect'fto the cylinder; of a valve Amechanism having. arev{stricted opening and also a Ylarge opening through Which iuid is supplied from the auxiliary reservoir to said equalizing -valve device and comprising a valve operable to close communication through said large' opening, a spring,V anda movable abutment subject on one side tolaux-iliary reservoirpressure and yalvedevice suppliesfluid Vfrom theraux-iliar'y V reservoir to the brake-Zcylinder.l Y

on theoppositej-lside'to theopposifng pressures of' the` brake pipe and V'sa-idspringV forconvtrolling Athe operation of said valve.

i y-In'testimony whereof I havehereunto set my hand, this 18th day ofV September, 1930. 

